Add internationalization support to Middleman Blog. Thanks to that idea and realization:

https://github.com/onemanstartup/middleman-blog

You can use frontmatter or path's ":lang" part for language indication. Also you can use local_articles helper in templates to select only articles with selected language.
While creating article with rake you can pick a lang option now.
Tests are provided. I haven't much cucumber experience, but it seems, it works. Sorry, if I have a mistakes. Also sorry for my bad English very much.

Also in that squashed commit are small typo fix and fix of the unsafe moment for optional path's parts.
Merge pull request #156 from Xanders/master

Add internationalization support
Remove 3.0 version of the extension
Fix gemspec and update dependencies
Update CHANGELOG
Update blog options documentation
Move helpers into their own file
Add Coveralls
Add Coveralls badge
Progress refactoring and commenting new blogging stuff
Merge pull request #174 from rriemann/implement-unlimited-summary-length

implement summary with unlimited length
More refactoring and cleanup
Add failure scenario with non-ascii-tag
Don't parameterize non-ASCII tag

Because `'☆☆☆'.parameterize` returns `''`
ruby 1.9.3 compatibility
Improve BlogData
Clean up CustomPages and fix a couple bugs
Slightly clean template.rb
Leverage the "addressable" gem to clean up all our URL templating by replacing them with an RFC 6570 URI templating implementation.

URI parameter extraction and substitution is now totally handled by addressable. We can now support RFC 6570 templates in addition to Sinatra-style colon-var templates for our templated URIs - in fact, RFC 6570 templates are now the default. Also, permalinks can now include data from any page frontmatter key simply by referencing it as a variable substitution.
Merge remote-tracking branch 'fukayatsu/non-ascii-tag'

Conflicts:
	lib/middleman-blog/tag_pages.rb